Estimation of circulating blood volume in infants using the pulse dye densitometry method

Area of Science:

• Neonatal physiology
• Pediatric critical care
• Hemodynamic monitoring

Background:

• Accurate hemodynamic assessment is crucial for critically ill infants.
• Pulse dye densitometry (PDD) with indocyanine green (ICG) is a novel bedside method for measuring circulating blood volume, previously established in adults.

Purpose of the Study:

• To evaluate the applicability and accuracy of PDD using ICG for hemodynamic monitoring in infants.
• To determine if PDD can reliably measure circulating blood volume in a neonatal population.

Main Methods:

• A validation study compared arterial indocyanine green concentrations measured by blood sampling (spectrophotometry) against noninvasive PDD measurements in seven infants.
• Circulating blood volume was subsequently estimated using the PDD method in 25 infants (gestational age 24-40 weeks).

Main Results:

• A strong positive correlation (r = 0.913, P < 0.0001) was observed between ICG concentrations measured by blood sampling and PDD.
• Bland Altman analysis showed minimal bias (-0.24 +/- 0.30 mg.l(-1)) and acceptable limits of agreement between the two methods.
• The mean (SD) blood volume measured by PDD was 94.9 (24.3) ml.kg(-1), consistent with previously reported values.

Conclusions:

• Pulse dye densitometry (PDD) utilizing indocyanine green (ICG) is a validated and accurate method for hemodynamic monitoring in infants.
• This noninvasive technique offers a reliable approach for bedside assessment of circulating blood volume in the neonatal population.